Does Extremem Hot Temps affect gas mileage?
 

For the last two weeks we have had every day above 105 degrees and some days up to 110. Since the temps have been so high my gas mileage is down to around 14.5 to 15 mpgs, which is real uncommon for this truck, its usually in the 17 to 19 range... Just wondering if these hot temps are the cause of the fuel mileage... I will say that 2wice this week i let the truck idle for maybe 20 mins with the ac on. Could that cause the mileage to drop this much.

Thanks

I'd say that's where your gas went... ;)

Mitch

While hot air is less dense than cold air, it would cause a slight decrease, maybe 1-2 mpg at max, but nothing that large.

20 minutes in retrospect to a full tank of gas isnt anything. I've idled my truck for a little more than an hour and a half and it only burned about half a gallon. And at cruise, my V6 loses about 1.2-1.5 mpg with max A/C. So I would look somewhere else- driving habits, different routes, etc.

well we live in texas, its hotter than satins pitchfork down here, id say that has a decent effect on the gas mileage

Im gonna try less idleing, and try not to run AC in the mornings, to see if it makes much of a difference. Usually by 8 in the morning its already 85 degress so the ac is on all day everyday. Would it make a differance if i maybe set my Edge to stock? Im running level two for the last 15k miles.

I think that all three things are what is eating your milage. The heat does seem to cut mine down a little. But idling with the A/C on is probably the biggest drain.

I notice here in So Cal. that when the traffic is real bad all week, my milage per tank is WAY down, slow traffic here is the same as idling while parked! When I get that rare week when the traffic is light and I can drive at a normal freeway speed the milage goes way up. That is just one reason I HATE drive thru's.

Here are some technical reasons for a loss in mileage in hot temps.
1. Air is less dense so less power is produced leading to increased throttle application leading to more fuel used for the same overall driving style.
2. The intake air temp sensor alters ignition timimg by going in the retard direction equalling less power and again more throttle application and using more gas.
3. Add extra load from A/C, passengers etc and you need more throtle to move the weight.
Add it all up and you surely will notice a drop in fuel mileage.
It's all normal action and reaction.
Good luck.

Thanks makes since... I have noticed on the intake air temp its been as high as 140 degress sitting and idleing :eek:. Wife is driving the truck this week which she does all highway driving and its looking like im back up to my regualr mpgs. So far she has 85 miles on the tank and it still sitting on the full mark... Will see how it does at the end of the week

Don't rely on the fuel gage position to quickly each time because it is digital driven and is updated at 'intervals' by the dash processor.
Between updates you may get a false impression and find sometimes it has fallen more since you last saw it, the next time you start the engine.
Any ways good luck.

The hotter it is, the more the A/C compressor runs to maintain temperature. It's been in the 90's around here all month and my mileage is way down.

Well after the wife driving all week got 285 miles on 17.4 gallons. Comes out to about 16.4 mpg's. So its better than last week, but still not as good as its always been. But also its usually around 82-85 degrees by 8 in the morning so the ac is always on all day everyday...

Yeah like Bluegrass stated, these are the factors in the fuel mileage going down. You also have the ethanol attempting to percolate out of the gas which causes the PCM to be constantly adjusting the A/F ratios and timing. Mine has been a lot lower since the summer finally arrived before spring came.